1. Field of the Invention
The present invention pertains generally to dispensing closures comprising a cap with a spout pivotally mounted on the cap. More particularly, the present invention pertains to unique standards and bearings located within a cavity in the upper surface of the cap to receive, and retain, the spout therewithin.
2. Background
The term, or expression, "dispensing closure" identifies a two (or more) component structure comprising a cap adapted to be mounted upon a container, and a spout (or lid) mounted on the cap for pivotal movement between opened, and closed, positions. The cap has a cavity in its upper surface, with bearing openings formed in the walls defining the cavity. Trunnions (or axles) are located on opposite sides of the enlarged base of the spout, and the trunnions are snapped into place within the bearing openings during the assembly of the dispensing closure.
U.S. Pat. No. 3,023,939, granted Mar. 6, 1962, to Henry A. Gustafson, discloses a representative dispensing closure. The closure includes a cap (10) with a top surface (14) and a threaded skirt (16); an opening (22) extends through the top to establish communication with the passage (38) in the spout (40). Axles (32) on the spout (30) are pushed through a slot (28) on the top of the cap and snapped into engagement with bearing openings (26). The spout is thus secured to the cap for pivotal movement relative thereto. The base of the spout presses against O-ring seal (24) which surrounds the opening (22) and compresses same (as shown in FIG. 4) to minimize leakage.
Another dispensing closure, and one that lends itself to high speed injection molding techniques, can be molded within narrow tolerance, is easy to assemble, and can be produced at a competitive price, is set forth in U.S. Pat. No. 4,209,114, granted on Jun. 24, 1980 to Woodrow S. Wilson et al. Wilson et al discloses a dispensing closure comprising a cap (12) including two spaced, aligned bearings (42), and a pivotally mounted spout (30) with trunnions (40) that fit within the bearings. At least one of the components of the dispensing closure is formed of a material, such as a linear polyethylene, or polypropylene, which is sufficiently resilient that the trunnions may be snapped into the bearings during the assembly of the dispensing closure. The trunnions are tapered (as shown in FIGS. 4 and 5), and the entrances (44) into the bearing openings are formed of two, nearly flat sloping walls (46) with curved edges (48). The trunnions and bearing openings retain the enlarged base (28) of the spout in the proper relationship to the opening (22) in the cap that communicates with the interior of the container to which the dispensing closure has been secured.
Another dispensing closure that lends itself to high speed injection molding techniques, ease of assembly, low cost, etc. is shown in U.S. Pat. No. 4,219,138, granted Aug. 26, 1980, to Robert E. Hazard. The dispensing closure disclosed in such patent utilizes a washer spring (40; 140) situated about the opening (38) in the cap (12) of the closure. The washer spring, which is integrally molded with the cap, resiliently biases its sealing surface (such as bead or ring 46) against the base (34) of the spout (14) of the closure. Trunnions (32; 132) on the spout are snapped into engagement with bearing openings (28; 128) in the walls of the cap to secure the spout to the cap for pivotal movement relative thereto.
The foregoing dispensing closures functioned satisfactorily, under most circumstances, and met with consumer acceptance. Nonetheless, leakage, even on an infrequent basis, continued to be a problem. The need for sealing rings about the opening in the cap to combat leakage of the product in the container, as disclosed in the Gustafson patent, was obviated by the improved congruency of contacting surfaces achieved by the Wilson et al and Hazard dispensing closures. However, in order to maintain the congruent surfaces on the base of the spout and the cap in contact, tighter tolerances were imposed on the molded components. The tighter tolerances were difficult and costly to maintain with high speed injection molding equipment, and problems were encountered in assembling the spouts to the caps so that the congruency necessary for sealing was maintained, at all times. Furthermore, minor imperfections in the plastic being molded caused excessive abrasion on the contacting surfaces, so that leakage persisted as a constant, irritating problem with known dispensing closures.